The researchers found that the animals eat the brains of infants, adolescents and juveniles first.

According to scientists, they have made a new discovery about chimpanzees’ diets.

An anthropologist from Arizona State University, Ian Gilby, led a team that discovered that the animals are systematic when preying on red colombus monkeys.

Notably, according to the team who made the discovery, the animals start eating the babies' brains when they capture the animals.

The gruesome habit may be linked to the nutritional quality of the brain, according to the researchers - and early human ancestors may have followed a similar path.

The researchers examined footage of chimps in Gombe National Park in Tanzania to learn about the ways in which the animals consume meat.

The researchers found that the animals eat the brains of infants, adolescents and juveniles first.

This led Gilby to wonder why the animals ate certain body parts first, and he reached the conclusion it has to do with the nutritional value of certain body parts.

Speaking to the National Geographic he said, “We tend to just say meat is meat, but we know that the nutrient composition varies. The whole carcass is valuable but the brain is especially valuable.”

He elaborated that the reason chimps head straight for babies' brains could have something to do with their accessibility: brains of adult colombus monkeys are not as easy to get to because predators would have to crack fully-formed skulls to get to them.

If a chimp were to try to kill an adult monkey they might not be able to get to its brains before a competing chimp snatched the prey from it.

Texas State University biological anthropologist Jill Pruetz told National Geographic,"[This] might be one of the first quantitative studies about how exactly a prey item is eaten by chimps."

Pruetz studies chimpanzees in Senegal, and she said she has witnessed similar behavior there.

Researchers believe that the habit, coming from a species that humans probably share a common ancestor with, likely speaks to human evolution.

According to Pruetz one of the best ways they have of understanding early hominids is using chimps as a model. Getting the clearest picture of chimpanzee hunting allowed them to make predictions about how the earliest hominids may have behaved.